Fluorinated silica supports containing organo-chromium compound or organomagnesium complexes were disclosed as a catalysts for the polymerization of ethylene and its copolymerization with other olefins in U.S. Pat. Nos. 4,100,337 and 4,359,403. The catalysts were prepared by mixing particles of reactive silica carrying superficial active --OH or oxide groups with a fluorine compound e.g., ammonium fluoride, ammonium tetrafluoroborate or ammonium hexafluorosilicate and heating the mixture at 50.degree.-700.degree. C. in presence of a solvent.
Japanese Patent Publication J03279209-A disclosed a procedure of fluorination of white silica particle from tetraethylorthosilicate with hydrogen fluoride and heating the mixture to 600.degree. C. to obtain fluorinated black silica particle.
U.S. Pat. No. 5,064,796 disclosed an olefin polymerization catalyst produced by reacting a fluorinated silica support with a vanadium compound. The fluorinated silica is produced by mixing silica with a fluorine compound e.g., hydrogen fluoride, ammonium fluoride or a metal fluoride at 200-1000.degree. C.
U.S. Pat. No. 4,822,903 disclosed a fluorinated siliceous catalyst for the catalytic synthesis of aromatic/aliphatic nitrites and is comprised of a plurality of silica particulates with the fluorine content ranging from about 0.1 to about 1% by weight based upon silica. The product gel was comminuted to grains which has a specific surface area ranging from about 200-250 m.sup.2 /g, an average pore volume ranging from about 1-1.3 cm.sup.3 /g and an average pore diameter ranging from about 100-150 A.sup.0. The fluorinated silica was characterized as a microporous acid silica at a pH 1-3 for use as a catalyst.